Second TBM Cutterhead Lowered For Mumbai-Ahmedabad Bullet Train Tunnel Project

By Business Vibes of India On May 24, 2026

By, Arun Kumar Das

MUMBAI, May 23: The National High Speed Rail Corporation Limited has achieved another major milestone in the Mumbai-Ahmedabad Bullet Train Project by successfully lowering the cutterhead of the second Tunnel Boring Machine (TBM) for the ambitious underground tunnel section near Mumbai.

The cutterhead was lowered at Sawli in Ghansoli, marking a crucial stage in the assembly of the giant tunnelling machine that will help construct the 21-kilometre underground stretch of the high-speed rail corridor.

Second TBM To Tunnel From Ghansoli To Vikhroli

According to officials, the second TBM will begin its tunnelling journey from Sawli (Ghansoli) towards Vikhroli.

The lowering of the cutterhead is considered one of the most technically demanding tasks in railway infrastructure construction due to the massive scale and precision required during assembly.

Earlier this week, the cutterhead for the first TBM was also lowered at Vikhroli, bringing both machines closer to operational readiness.

Massive 350-Tonne Cutterhead Installed

The cutterhead installed for the second TBM has a diameter of 13.6 metres and weighs approximately 350 tonnes. It forms the front section of the machine and is responsible for cutting through soil and rock during tunnelling operations.

The component marks the final major stage in assembling the TBM’s main shield before full commissioning and trial operations begin.

TBMs Expected To Begin Work In July 2026

Officials stated that both Tunnel Boring Machines will now undergo final assembly procedures and commissioning trials before starting excavation work in the first week of July 2026.

The two TBMs are designed to construct a single large tunnel capable of accommodating both the up and down lines of the high-speed rail corridor.

Advanced Engineering Features Of The TBMs

The giant machines are equipped with advanced tunnelling systems designed for high-efficiency underground excavation. Each TBM includes:

84 cutter discs
124 scrapers
16 bucket lips

These components help in cutting, crushing, and removing excavated material during tunnelling operations.

The machines are also fitted with several major engineering systems, including the cutter wheel, main bearing, jaw crusher, erector, main shield, tail shield, and four specialised gantries used for tunnel construction support.

Dimensions And Operational Capacity

The first TBM weighs around 3,080 tonnes, while the second weighs approximately 3,184 tonnes. Both machines measure about 95.32 metres in length.

The TBMs can operate at a maximum cutterhead speed of 4 RPM and achieve excavation speeds of up to 49 milli metres per minute, allowing steady progress while maintaining safety and structural stability underground.

The Mumbai-Ahmedabad Bullet Train project remains India’s first high-speed rail corridor and is among the country’s largest infrastructure initiatives currently under construction.